To recap here:
My sister's dog answer's to it's name, "little bunny," and a combination of the two.
The cat (who has become my father's cat, apparently) was raised by a dog and never quite figured out that she is a cat, which makes her this wonderful cat/dog mix that is perfect.
The guinea pig has been hanging out with the hermit crabs too long and is learning things.
She's obviously not stuck, since she does this with any of the houses (Mom likes to switch them up sometimes) and gets out of them all the time.
Just thought you all should know.